This application claims the priority benefit of Japanese application serial no. 2001-174776, filed on Jun. 8, 2001.
1. Field of the Invention
This invention relates in general to an image formation apparatus, such as a copy machine, a printer or a FAX machine, and a developing apparatus and a process cartridge that are used in the image formation apparatus. More specifically, the invention relates to a developing apparatus, and an image formation apparatus and a process cartridge having the developing apparatus, wherein the developing apparatus has a self toner concentration controlling machine capable of controlling the toner concentration in the developer on a developer carrier within a preset range, by using a two-component developer containing toner and magnetic carrier, and without using a complicated toner supply device.
2. Description of Related Art
One of the conventional developing apparatuses is disclosed by Japanese Laid Open H09-22179. In the developing apparatus, the amount of the developer is regulated by a developer-regulating unit, wherein the developer is carried on a developer carrier having a magnetic field generating device therein. The developer collected by the developer-regulating unit is contained in a developer container. From the toner supply gate, that is opposite to the developer carrier and is adjacent to the upstream side of the developer transfer direction in the developer container, the toner in the toner container is supplied to the developer on the developer carrier. In the developing apparatus, the toner, in contact with the developer that is carried and transferred on the developer carrier at the toner supply gate, is taken into the developer from an interface between the transferred developer and the developer contained in the developer container. As the toner concentration of the developer in the developer increases, because the volume of the developer increases, the developer contained in the developer container extends so as to cover the toner supply gate, thereby the feeding of the developer from the toner container at the toner supply gate to the developer can be suppressed. In this way, the toner concentration of the developer in the developer carrier can be controlled within a preset range. In addition, Japanese Laid Open H09-197833 discloses a developing apparatus, in which a second developer-regulating unit with a preset gap with respect to the surface of the developer carrier is set between the developer container and the toner supply gate of the toner container. In the developing apparatus, as the toner concentration of the developer in the developer carrier increases, the thickness of the developer increases. The passing of the increased developer is regulated by the second developer-regulating unit. The regulated developer covers the toner supply gate that is adjacent to the upstream side of the developer transfer direction with respect to the second developer-regulating unit, so that the feeding of the toner from the toner container to the developer carried and transferred on the developer carrier can be suppressed. Thereby, the toner concentration of the developer in the developer carrier can be controlled within a preset range.
According to the above developing apparatus to control the toner concentration of the developer in the developer carrier within a preset range (self toner concentration control), because the toner concentration sensor is not required and the stirring device such as a paddle screw etc can be omitted, the toner supply device can be simplified. Furthermore, in comparison with the conventional two-component developing method, the magnetic carrier can be reduced and the torque of the developing apparatus can be significantly reduced. As a result, the device can become smaller and more compact, and the cost can be reduced. Moreover, because the toner in the toner container can be directly supplied to the developer in the developer carrier passing through the developing area, the toner can be quickly supplied to a portion of the developer where the toner concentration decreases. Therefore, the forming ability for the black solid image is excellent.
In comparison with the conventional two-component developing method, in the developing apparatus that performs the self toner concentration control by only a few magnetic carriers, because the initial developer has to be uniformly set in the developer carrier, an initial developer container is installed in the vicinity of the developer container, and at the beginning of use, the user strips off a sealing material that separates the initial developer container from the developer container, so that the initial developer is filled into the initial developer container. In addition, in order to prevent the toner from acuminating in the toner supply unit with a toner supply gate near the developer carrier and to prevent the toner from scattering out of the toner container, a sealing material is installed for separating the toner container from the toner supply unit. This sealing material will be also stripped off by the user at the beginning of use. After the sealing material is stripped off, the developing apparatus is set into the printer, and then the toner supply unit installed in the developer carrier and the toner container rotates via gears at the same time. Then, it begins to send the initial developer to the developer carrier or begins to supply the toner to the toner supply unit.
However, at the location to strip off the sealing materials, in order to maintain a working space for stripping off the sealing materials in the longitudinal direction of the developing apparatus, i.e., the central axis line of the developer carrier, it happens that the sealing materials are stripped off under a condition that the developing apparatus is tilt. When the sealing materials are stripped off under a condition that the developing apparatus is tilt, the initial developer in the initial developer container moves to one end along the central axis line of the developer carrier, which causes the initial developer to be not uniformly set on the developer carrier along the central axis line of the developer carrier. Therefore, the toner will be over supplied to the insufficient developer area having little developer, and therefore as the toner concentration increases, abnormal image due to contamination occurs. In contrast, the developer will be scattered in the developer area having much developer. In addition, in the developing apparatus, because no stirring mechanism is provided to cycle the developer along the central axis line of the developer carrier and to stir the developer, once the initial developer is not uniformly set, the non-uniform developer problem cannot be solved, so that the abnormal image due to contamination or the developer scatter continuously occurs.
According to the foregoing description, an object of this invention is to provide a developing apparatus, an image formation apparatus and a process cartridge, by which even though the sealing material is installed on the initial developer throwing opening of the initial developer container under a condition where the developing apparatus is tilt, the initial developer can be uniformly supplied along the central axis line of the developer carrier.
According to the object(s) mentioned above, the invention provides a developing apparatus, comprising a developer carrier, a developer regulating unit, a developer container, a toner container, an initial developer container, and a sealing material. The developer carrier has a magnetic field generating device therein, for carrying a developer containing a toner and a magnetic carrier and transferring the developer to move on a surface of the developer carrier. The developer regulating unit is used for regulating an amount of the developer that is carried on the developer carrier and transferred towards a developing area. The developer container is used for containing the developer that is regulated by the developer regulating unit and transferred towards a developing area. The toner container has a toner supply gate facing a surface of the developer carrier at a position adjacent to an upstream side of a developer transfer direction in the developer container. The initial developer container is used for containing a non-used initial developer that is thrown to the initial developer container. The sealing material is used for sealing an initial developing throwing opening installed on one side of the developer container of the initial developer container, and capable of being stripped off along a central axis line of the developer carrier. By moving the developer when the developer is transferred on the developer carrier, the toner in the toner container is taken into the developer according to a toner concentration of the developer on the developer carrier. Furthermore, a plurality of partitions is formed inside the initial developer container so that a plurality of partition spaces is divided along the central axis line of the developer carrier inside the initial developer container, and wherein based on the initial developer throwing opening, a partition surface facing to the partition space of each partition is tilted to one end of the central axis line of the developer carrier with respect to an imaginary plane perpendicular to the central axis line of the developer carrier.
According to the above developing apparatus, at the beginning of use, in the two ends of the central axis line of the developing apparatus, the tilt direction of the partition surface of each partition is set to one end located at lower side in the vertical direction when the developing apparatus is tilted for stripping off the developer sealing. As the developing apparatus is tilted, because the direction of stripping off the sealing material is tilted from the horizontal direction, the working space in the horizontal direction for stripping of the sealing material can be maintained in comparison with that the sealing material is stripped off in the horizontal direction.
Furthermore, when the developing apparatus is tilted towards the preset direction, the difference in vertical height between one end of the initial developer throwing opening of the partition surface faced under each partition space of the initial developer container and the opposite end is smaller than that in the conventional developing apparatus that the partition surface is not tilted but formed along the imaginary surface. Otherwise, the vertical height of the initial developer throwing opening of the partition surface is higher than its opposite end. Thereby, in comparison with the conventional developing apparatus, the initial developer in each partition space is hardly to move near the initial developer throwing opening, and therefore the initial developer can be easily maintained in the each partition space. Accordingly, even though the sealing material is stripped off under the condition that the developing apparatus is tilted in the preset direction, it can suppress the initial developer in each partition space from falling into the initial developer container due to gravity.
Therefore, after the sealing material is stripped off and when the developing apparatus returns to the non-tilt status in common use from the status that the developing apparatus is tilted in the preset direction, and because the initial developer existing in each partition space of the initial developer container can be slowly filled into the developer container installed along the surface of the developer carrier, the initial developer can be uniformly supplied along the central axis line of the developer carrier.
As described above, because there is no deviation in that the initial developer is uniformly supplied along the central axis line of the developer carrier, and the self toner concentration control is performed so that the toner concentration of the developer on the developer carrier can be well controlled within a certain range, it can prevent contamination because the toner will be over supplied to the insufficient developer area, or can prevent the developer from being scattered in the developer area having much developer.
The above developing apparatus further comprises a second developer regulating unit located between the toner supply gate of the toner container that faces the surface of the developer carrier, for regulating the amount of the developer on the developer carrier that is carried and transferred towards the developer container from the opposite side of the toner container. A gap can be set between the second developer regulating unit and the surface of the developer carrier, so that the regulated amount of the developer increases when the toner concentration of the developer on the developer carrier increases. In this situation, by using the second developer regulating unit, the toner concentration can be stably controlled without being affected by the magnetic unevenness on the developer carrier.
In addition, the above partition is formed with a plate shape, and each of the partitions is tilted with respect to an imaginary plane.
Accordingly, by tilting the partitions that are formed with a plate shape, the tilt of the partition surface can be easily set, and the occurrence of the dead space in the initial developer container due to forming the partitions can be minimized.
The initial developer container has a sidewall perpendicular to the partition surface of each partition, and openings are formed on the sidewall to expose side ends of the partitions, and after the initial developer is filled into each partition of the initial developer container, a sealing material is set to seal the openings formed on the sidewall of the initial developer container.
Accordingly, when forming the initial developer container using the mold, because the mold can be removed by sliding along the partition surface of each partition through the opening formed on the sidewall, it is not needed to prepare a mold with a particular structure to form the initial developer container having the tilted partitions therein. In addition, after the initial developer is filled into each partition space of the initial developer container, because the partition spaces are sealed by sealing the openings, which are formed on the sidewall of the initial developer container for removing the mold, with the sealing material, the initial developer can be prevented from leakage.
The sealing material can use for example a thermal welding sheet that is widely used in fields such as the developing apparatus. The welded sealing material covers the openings of the initial developer container, and by heating and welding the side ends of the partitions exposed to the openings and the surroundings of the openings, the openings are then sealed. In addition to the thermal welding, the sealing material can be installed by supersonic welding or vibrational welding, or can be adhered by using the double-side tape or the adhesive.
The invention further provides an image formation apparatus, comprising a latent image carrier, a latent image formation device, a developing apparatus, and a transcribing device. The latent image formation device is used for forming a latent image on the latent image carrier. The developing apparatus is used for developing the latent image on the latent image carrier to form a toner image, and can be the developing apparatus mentioned above and is capable of detaching or attaching to the image formation apparatus. The transcribing device is used for transcribing the toner image on the latent image carrier to a transcriber.
Accordingly, before assembling the developing apparatus to the image formation apparatus, by stripping off the sealing material in such a way that the process cartridge having the developing apparatus is tilted to the preset direction, the working space for stripping off the sealing material can be easily maintained. Furthermore, the initial developer in the initial developer container can be uniformly supplied along the central axis line direction of the developer carrier. By installing the developing apparatus such that the initial developer is uniformly supplied to the image formation apparatus, the contamination or developer scattering can be prevented.
The invention also provides a process cartridge, comprising: a latent image carrier and a developing apparatus. The developing apparatus is used for developing the latent image on the latent image carrier to form a toner image. The developing apparatus is the developing apparatus mentioned above and is capable of detaching or attaching to the image formation apparatus. The process cartridge is integrally formed and detachable from the image formation apparatus.
In the above process cartridge, before assembling the developing apparatus to the image formation apparatus, by stripping off the sealing material in such a way that the process cartridge having the developing apparatus is tilted to the preset direction, the working space for stripping off the sealing material can be easily maintained. Furthermore, the initial developer in the initial developer container can be uniformly supplied along the central axis line direction of the developer carrier. By installing the process cartridge so that the initial developer is uniformly supplied to the image formation apparatus, the contamination or developer scattering can be prevented.
In addition to the latent image carrier and the developing apparatus, the process cartridge further includes at least one of a charging device for charging the latent image carrier or a cleaning device for cleaning the latent image carrier.